Research on Multi-View Phase Shift and Highlight Region Treatment for Large Curved Parts Measurement

For large curved parts with complex surfaces, which often exhibit both symmetry and asymmetry in their geometric features, the multi-view combined with the phase shift method and highlight regions treatment method has been proposed and applied to the online measurement system. The hardware components of the measuring system include a self-designed multi-vision platform and a multi-view three-dimensional measurement platform composed of rotating platform, robot and linear guide rail. The overall calibration of the system was conducted to guarantee the effectiveness of the measurement point cloud splicing of each viewing angle. And the system integrates the three-dimensional measurement technology of multi vision combined with the phase shift method and online measure system to realize full coverage and high-precision measurement of the impeller—addressing both its inherent symmetry (regular blade arrangement) and local asymmetry (irregular edge details)—and controls the relative error of the measured size and the actual size within 1%. In addition, the highlight regions treatment method has also been proposed. By adjusting the camera’s exposure time to change the light intensity of the captured images, images under different exposures and their valid pixels are obtained, thereby facilitating the synthesis of a composite image free of highlight phenomena. Experimental results demonstrate that the proposed method can achieve full-coverage measurement of the measured object and effective measurement of highlight regions.